This is the meaning of their statement 'and he led his...

This is the meaning of their statement 'and he led his sessions in theology and inquiry.' It enabled him to come into contact with the majority of those whose normal circumstances would not have permitted them to meet a distinguished theologian like Hisham, who would listen to their views and arguments, let them debate with one another, and then supervise the procedure of inquiry, and evaluate the arguments and give the correct view.

al-Mas‘udi tells of one such session: Yahya ibn Khalid ibn Barmak, a man of knowledge and discernment, and upholder of discussion and the giving of opinion, used to bring together many discussants and holders of opinion from the mutakallims of Islam and other thinkers and sectarians. Yahya said to them one day when they had gathered at his house: 'You have had many discussions about latency (kumun), manifestation (zuhur), and eternity…